Sahih Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Volume: 005 / Book Number: 059 / Hadith Number: 667
Narrated Abu Musa:
My brother and I came from Yemen (to Medina) and remained for some time, thinking that Ibn Masud and his mother belonged to the family of the Prophet because of their frequent entrance (upon the Prophet) and their being attached to him.